For sending mail, you should use smtp.aqnet.co.uk [N.B. This will require SMTP authentication].
For collecting you mail via POP3 you should use pop.aqnet.co.uk.
For collecting your mail via IMAP you should use imap.aqnet.co.uk
For access to your email via the Internet, if you have that feature enabled, use http://webmail.aqnet.co.uk.
For full details see: http://www.aquatechnologies.co.uk/support/mail/